FN Archimer Export Format
PT J
TI Origin of primitive ocean island basalts by crustal gabbro assimilation and multiple recharge of plume-derived melts
BT 
AF BORISOVA, Anastassia Y.
   BOHRSON, Wendy A.
   GREGOIRE, Michel
AS 1:1,2;2:3;3:1;
FF 1:;2:;3:;
C1 Univ Toulouse, Geosci Environm Toulouse, CNRS, UPS OMP,IRD, 14 Ave E Belin, F-31400 Toulouse, France.
   Lomonosov Moscow State Univ, Dept Geol, Moscow 119899, Russia.
   Cent Washington Univ, Dept Geol Sci, Ellensburg, WA 98926 USA.
C2 UNIV TOULOUSE, FRANCE
   UNIV MV LOMONOSOV MOSCOW STATE, RUSSIA
   UNIV WASHINGTON, USA
IF 2.981
TC 10
UR https://archimer.ifremer.fr/doc/00393/50409/51128.pdf
   https://archimer.ifremer.fr/doc/00393/50409/51133.pdf
   https://archimer.ifremer.fr/doc/00393/50409/51134.xlsx
LA English
DT Article
CR KERIMIS-MD109
BO Marion Dufresne
DE ;ocean island basalt;Kerguelen;mantle plume;ocean metagabbro xenoliths;crustal assimilation and fractional crystallization;Magma Chamber Simulator
AB Chemical Geodynamics relies on a paradigm that the isotopic composition of ocean island basalt (OIB) represents equilibrium with its primary mantle sources. However, the discovery of huge isotopic heterogeneity within olivine-hosted melt inclusions in primitive basalts from Kerguelen, Iceland, Hawaii and South Pacific Polynesia islands implies open-system behavior of OIBs, where during magma residence and transport, basaltic melts are contaminated by surrounding lithosphere. To constrain the processes of crustal assimilation by OIBs, we employed the Magma Chamber Simulator (MCS), an energy-constrained thermodynamic model of recharge, assimilation and fractional crystallization. For a case study of the 21–19 Ma basaltic series, the most primitive series ever found among the Kerguelen OIBs, we performed sixty-seven simulations in the pressure range from 0.2 to 1.0 GPa using compositions of olivine-hosted melt inclusions as parental magmas, and metagabbro xenoliths from the Kerguelen Archipelago as wallrock. MCS modeling requires that the assimilant is anatectic crustal melts (P2O5  ≤ 0.4 wt.% contents) derived from the Kerguelen oceanic metagabbro wallrock. To best fit the phenocryst assemblage observed in the investigated basaltic series, recharge of relatively large masses of hydrous primitive basaltic melts (H2O = 2–3 wt%; MgO = 7–10 wt.%) into a middle crustal chamber at 0.2 to 0.3 GPa is required. Our results thus highlight the important impact that crustal gabbro assimilation and mantle recharge can have on the geochemistry of mantle-derived olivine-phyric OIBs. The importance of crustal assimilation affecting primitive plume-derived basaltic melts underscores that isotopic and chemical equilibrium between ocean island basalts and associated deep plume mantle source(s) may be the exception rather than the rule. 
PY 2017
PD JUN
SO Geochemistry Geophysics Geosystems
SN 1525-2027
PU Amer Geophysical Union
VL 18
IS 7
UT 000407477800018
BP 2701
EP 2716
DI 10.1002/2017GC006986
ID 50409
ER

EF